The ultimate goal of this research program is to determine the chemical structure and biological function of the nonhistone chromosomal proteins (NHC proteins) of Drosophila. Particular emphasis will be placed on studying the heterogeneity of these proteins, their role in maintaining chromatin structure, and their role in the general mechanism of gene activation. Initial work will aim at the isolation and chemical characterization of the NHC proteins; concurrently, antibodies will be made to the total and isolated NHC proteins. The use of labeled antibody techniques to provide specific "stains" for the NHC proteins will allow one to answer many important questions concerning the distribution and role of the NHC proteins in vivo. The information and techniques developed, coupled with information on enzymic properties of NHC proteins, will provide the means to start to trace the sequence of biochemical events in gene activation as it occurs in the salivary gland polytene chromosomes of Drosophila in response to hormone stimuli, etc.